The present invention relates to an electro-optical device that can change a display resolution.
In an electronic apparatus, such as a cellular phone, with an increase of the information amount, it is necessary to display an image with a high density. Accordingly, a resolution of a display device has been increasing every year. On the other hand, since the information transfer rate in a communication apparatus is insufficient and thus it is difficult to distribute high-resolution moving pictures, there are cases in which low-resolution images are distributed.
When the low-resolution images are displayed on a high-resolution display device, the display is made using only a portion of a screen, and thus a resolution conversion device is required. As the resolution conversion device, generally, a digital signal processor (DSP) or the like has been used. In this case, however, an increase in cost, a delay of the conversion process, or the like may occur.
For this reason, a technique has been suggested, in which a modulated clock signal is used as a clock signal to a shift register in order to select scanning lines and the scanning lines are sequentially selected two by two, such that the resolution in a scanning direction becomes a half (see Japanese Unexamined Patent Application Publication No. 2001-249639 (FIG. 4)).
However, in the above-described configuration, the modulated clock signal, which is used to display the low-resolution image, needs to have a different duty ratio from a reference clock signal, which is used to display a normal high-resolution image. For this reason, actually, the modulated clock signal needs to be generated from the reference clock signal or needs to be separately generated from the reference clock signal. As a result, the configuration is complicated.